audio missing from edited video
i could not find encoding and audio codec in my properties panel


That might be the reason. Probably you did (and could) not set any audio properties. Follow these steps:


Go onto the render page in properties window:





Scroll down to the output-tab and select a movie format as output format. Be sure that this format supports more encoding properties. Means: once selected directly under the output-tab a tab called "Encoding" should appear. If I can give you an advice choose H.264 as output format.





In encoding tab, choose your preferred Movie format. In the bottom part of the tab, choose an Audio codec different from "None". For example MP3 (if an average quality of the audio is sufficient).




Hope these steps and advices worked well :)

Greets
Jaspa